Waveguide compositions and waveguides formed therefrom

ABSTRACT

Provided are compositions suitable for use in forming a flexible optical waveguide. The compositions include a polymer, having units of the formula (RSiO 1.5 ), wherein R is a substituted or unsubstituted organic group, and a plurality of functional end groups. A first component is provided for altering the solubility of the composition in a dried state upon activation. A second component contains a plurality of functional groups chosen from hydroxy, amino, thiol, sulphonate ester, carboxylate ester, silyl ester, anhydride, aziridine, methylolmethyl, silyl ether, and combinations thereof. The second component is present in an effective amount to improve flexibility of the composition in a dried state before and after activation. Also provided are flexible optical waveguides, methods of forming flexible optical waveguides and electronic devices that include a flexible optical waveguide.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. § 119(e) of U.S.Provisional Application No. 60/524,820, filed Nov. 25, 2003, the entirecontents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of waveguides. Inparticular, the present invention relates to compositions suitable foruse in forming flexible optical waveguides. The invention furtherrelates to methods of forming flexible optical waveguides. As well, theinvention relates to flexible optical waveguides and to electronicdevices that include a flexible optical waveguide.

Signal transmission using pulse sequences of light is becomingincreasingly important in high-speed communications. For example,optical integrated circuits (OICs) are gaining importance for highbandwidth optical interconnects. As a result, the integration of opticalcomponents such as waveguides, filters, optical interconnects, lenses,diffraction gratings, and the like, is becoming increasingly important.

Optical waveguides are typically constructed by surrounding a corematerial with a clad layer. Optical radiation propagates in the corematerial because the clad layer has a lower index of refraction than thecore material. Waveguides may be used individually or as an arraysupported on a substrate. The waveguides often perform a passivefunction on the optical radiation. For example, splitters divide anoptical signal in one waveguide into two or more waveguides; couplersadd an optical signal from two or more waveguides into a smaller numberof waveguides; and wavelength division multiplexing (“WDM”) structuresseparate an input optical signal into spectrally discrete outputsignals, each of which couples to separate waveguides, usually byemploying either phase array designs or gratings. Spectral filters,polarizers, and isolators may be incorporated into the waveguide. Aswell, waveguides may alternatively contain active functionality, whereinthe input signal is altered by interaction with a second optical orelectrical signal. Exemplary active functionality includes amplificationand switching such as with electro-optic, thermo-optic or acousto-opticdevices.

Waveguide substrates include, for example silicon wafers and circuitbackplanes for use in server devices. The ability to handle waveguideswithout crack defects in the core and/or cladding materials isdesirable. The cracking property generally is a result of brittleness inthe coating material. Many organic polymer-based waveguides such aspolyimides are flexible, but have other drawbacks such as moistureabsorption, high losses and expense. Silicon-based systems, whichaddress various shortcomings of organic polymer systems, are generallybrittle resulting in crack defects as a result of handling.

Photoimageable waveguide cores have been proposed wherein portions ofthe coating are dissolved in an organic solvent to generate the desiredstructures. This technique has the drawback of using organic solventsthat are difficult to dispose of, waste treat and/or contain in a closedenvironment. It is therefore desirable to have the option of usingaqueous developers to create waveguide structures from photoimageablecoatings.

Hybrid silicon-carbon polymer systems have been proposed which addressbrittleness in interlayer dielectric coatings, especially for poregenerating compositions, for microcircuit applications. (See, e.g.,Chandross et al, U.S. Pat. No. 6,251,486) disclose a modifiedmethylsilsesquioxane composition for use as a low dielectric material.The methylsilsesquioxane includes dimethyl and phenyl pendant groups toprovide better crack resistance than an all methylsilsesquioxane. Thus,crack resistance is achieved for the coated article throughincorporation of the pendant groups into the polymer prior to coating.The choice of pendant groups and amounts are limited. It would,therefore, be desirable to improve flexibility by use of a componentseparate from the polymer in the composition being coated, as this wouldallow for an increase in the choices and amounts of suitable materials.There is thus a need in the art for compositions suitable for use inmanufacturing optical waveguides, which compositions provide beneficialflexibility characteristics while also being developable in an aqueousdeveloper solution. As well, there is a need in the art for waveguidesformed from these compositions, for methods of forming such waveguides,and for electronic devices that include such waveguides.

SUMMARY OF THE INVENTION

One aspect of the invention provides compositions suitable for use inmanufacturing flexible optical waveguides. The compositions include apolymer, having units of the formula (RSiO_(1.5)), wherein R is asubstituted and/or unsubstituted organic group and the polymer has aplurality of functional end groups; a first component for altering thesolubility of the composition in a dried state upon activation; and asecond component containing a plurality of functional groups, chosenfrom hydroxy, amino, thiol, sulphonate ester, carboxylate ester, silylester, anhydride, aziridine, methylolmethyl, silyl ether, andcombinations thereof. The second component is present in an effectiveamount to improve flexibility of the composition in a dried state beforeand after activation. The solubility of the composition in a dried stateis alterable upon activation of the component such that the compositionis developable in a developer solution.

In a second aspect of the invention, a flexible optical waveguide isprovided. The waveguide has a core and a clad, wherein the core and/orthe clad are formed from a composition that includes a polymer havingunits of the formula (RSiO_(1.5)), wherein R is a substituted and/orunsubstituted organic group and the polymer has a plurality offunctional end groups; a first component for altering the solubility ofthe composition in a dried state upon activation; and a second componentcontaining a plurality of functional groups, chosen from hydroxy, amino,thiol, sulphonate ester, carboxylate ester, silyl ester, anhydride,aziridine, methylolmethyl, silyl ether, and combinations thereof. Thesecond component is present in an effective amount to improveflexibility of the composition in a dried state before and afteractivation. The solubility of the composition in a dried state isalterable upon activation of the component such that the composition isdevelopable in a developer solution.

In a third aspect of the invention, provided is an electronic devicethat comprises a flexible optical waveguide as described above.

In a fourth aspect of the invention, methods of forming a flexibleoptical waveguide are provided. The methods involve: (a) forming a layerover a substrate from a composition that includes: a polymer, having:polymerized units of the formula (RSiO_(1.5)), wherein R is asubstituted and/or unsubstituted organic group and the polymer has aplurality of functional end groups; a first component for altering thesolubility of the composition in a dried state upon activation; and aand a second component containing a plurality of functional groups,chosen from hydroxy, amino, thiol, sulphonate ester, carboxylate ester,silyl ester, anhydride, aziridine, methylolmethyl, silyl ether, andcombinations thereof; wherein the second component is present in aneffective amount to improve flexibility of the composition in a driedstate before and after activation; and wherein the solubility of thecomposition in a dried state is alterable upon activation of thecomponent such that the composition is developable in a developersolution; and (b) activating at least a portion of the layer wherein thelayer is a core or a clad layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be discussed with reference to the followingdrawings, in which like reference numerals denote like features, and inwhich:

FIG. 1( a)–(e) illustrates in cross-section an optical waveguide atvarious stages of formation thereof, in accordance with one aspect ofthe invention; and

FIG. 2 illustrates an exemplary electronic device in accordance with oneaspect of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides compositions suitable for use in formingflexible optical waveguides. Unless otherwise specified, amounts forcomponents of the composition are given in weight % based on thecomposition absent any solvent. As used herein, the term “polymer”includes oligomers, dimers, trimers, tetramers and the like, andencompasses homopolymers and higher order polymers, i.e., polymersformed from two or more different monomer units and heteropolymers. Theterm “alkyl” refers to linear, branched and cycloalkyl groups, which aresubstituted or unsubstituted and can include heteroatoms in or on thechain. The term “aromatic” refers to aromatic groups, which aresubstituted or unsubstituted and can include heterocycles. The terms “a”and “an” mean “one or more”.

The term “in a dried state” means a composition containing 10 wt % orless of a solvent, based on the entire composition. The term “whereinthe solubility of the composition in a dried state is alterable” meansthat the solubility of the composition is alterable for any (notnecessarily every) solvent content in the range of 10 wt % or less.

The term “developable in an aqueous developer” means that, in the caseof a negative-working material, the composition, when (i) coated to athickness of 8 μm in a dried state on a silicon wafer, and (ii) thenplaced in a 2N NaOH developer solution, a 2N KOH developer solution or a2N TMAH developer solution, or a 1N solution thereof, or a 0.7N solutionthereof, or even a 0.26N solution thereof at a temperature of from 70 to180° F. (21 to 82.2° C.) with either static or spray developing at 40psi impinging spray and is completely dissolved within ten minutes, orwithin two minutes, or even within one minute, or even within 30seconds. The composition can additionally or alternatively bedevelopable in an organic solvent.

The term “flexible” or “flexibility” as it relates to the describedoptical waveguides refers to the ability of the compositions to becoated onto copper foil and, in the dried state, bent around a conicalMandrel bar without cracking or crazing. The specifics of the conicalMandrel test are well know in the coatings industry as exemplified byASTM D522-93a (Reapproved 2001).

The compositions include a polymer that has polymerized units of theformula (RSiO_(1.5)), wherein R is a substituted or unsubstitutedorganic group, and the polymer has a plurality of functional end groups.The compositions further include a component for altering the solubilityof the composition upon activation. The compositions further include acomponent containing a plurality of functional groups chosen fromhydroxy, amino, thiol, sulphonate ester, carboxylate ester, silyl ester,anhydride, aziridine, methylolmethyl, silyl ether, and combinationsthereof in an amount effective to improve flexibility of the compositionin a dried state before and after activation. The solubility of thecomposition in a dried state is alterable upon activation of thecomponent such that the composition is developable in an aqueousdeveloper solution.

The polymers useful in the present invention include, for example,siloxanes, silsesquioxanes, and caged siloxanes and combinationsthereof. The polymer may be present in the composition in an amount offrom 1 to 99.5 wt %, for example from 60 to 98.5 wt %. Exemplary organicgroups for R include substituted and unsubstituted alkyl, aryl andheterocyclic groups. The alkyl groups can be straight chain, branched orcyclic having, for example, from 1 to 20 carbon atoms, and typicallyhave from 1 to 20 carbon atoms, such as methyl, ethyl, propyl,isopropyl, t-butyl, t-amyl, octyl, decyl, dodecyl, cetyl, stearyl,cyclohexyl, and 2-ethylhexyl. The alkyl groups can be substituted withheteroatoms in and/or on the alkyl chain, for example, or can benon-aromatic cyclic groups such as cyclopentyl, cyclohexyl, norbonyl,adamantly, piperidinyl, tetrahydrofuranyl and tetrahydrothiophenylgroups. Exemplary aryl groups include those having from 6 to 20 carbonatoms, for example, from 6 to 15 carbon atoms, such as phenyl, tolyl,benzyl, 1-naphthyl, 2-naphthyl and 2-phenanthryl, and can be substitutedwith heteroatoms. Heterocyclic groups can be aromatic, for example,thiophene, pyridine, pyrimidine, pyrrole, phosphole, arsole, and furane.

Typical for R is a substituted and unsubstituted methyl, ethyl, propyl,cyclopentyl, cyclohexyl, benzyl, phenyl, adamantyl groups, andcombinations thereof.

The polymer can take the form of a copolymer or higher order polymer,either random- or block-type. The polymer can include, for example, oneor more additional silicon-containing unit, with the proportions foreach unit ranging from 1 to 85 wt %, for example, from 15 to 80 wt % orfrom 25 to 60 wt %, or from 25 to 50 wt %, based on the polymer. Theadditional units can, for example, be represented as siloxanes,silsesquioxanes, cage siloxanes and/or combinations thereof. Forexample, the polymer can further include polymerized units of theformula (R¹SiO_(1.5)), wherein R¹ is a substituted or unsubstitutedorganic group as described above with respect to R. One of R and R¹ can,for example, be chosen from substituted or unsubstituted alkyl groups,and the other of R and R¹ chosen from substituted or unsubstituted arylgroups.

The polymer can be, for example, an alkyl silicon polymer such as acopolymer containing methyl silsesquioxane units and butylsilsesquioxane units; an aryl silicon polymer such as a copolymercontaining phenyl silsesquioxane units andtrifluoromethylphenyl-silsesquioxane units or an aralkyl siliconcopolymer such as a copolymer containing methyl and phenylsilsesquioxane units.

As described above, the side chain groups of the polymer can beoptionally substituted. “Substituted” means that one or more hydrogenatoms on the side chain groups is replaced by another substituent group,for example, deuterium, halogen such as fluorine, bromine, and chlorine,(C₁–C₆)alkyl, (C₁–C₆)haloalkyl, (C₁–C₁₀)alkoxy, (C₁–C₁₀)alkylcarbonyl,(C₁–C₁₀)alkoxycarbonyl, (C₁–C₁₀)alkylcarbonyloxy, alkylamine,alkylsulfur containing materials, and the like. The polymers may containa wide range of repeating units, either random or block. The polymerunits useful in the present invention may have, for example, from 5 to150 repeating units, typically from about 10 to 35 repeating units; andthe siloxane units useful in the present invention may have for examplefrom 5 to 150 repeating units, typically from about 7 to 25 repeatingunits. Thus, the polymer may vary widely in molecular weight. Typically,the polymers have a weight average molecular weight (M_(w)) of fromabout 500 to 15,000, more typically from about 1000 to 10,000, even moretypically from about 1000 to 5000. It has been found that thedissolution rate of the compositions in accordance with the invention inan aqueous developer decreases with an increase in the molecular weightM_(w) and number average molecular weight, M_(n).

The polymers further include two or more functional end groups thatallow condensation polymerization to occur. Such end groups can be, forexample, hydroxy; alkoxy such as ethoxy, propoxy, isopropoxy;carboxyester, amino, amido, epoxy, imino, carboxyacid, anhydride,olefinic, acrylic, acetal, orthoester, vinyl ether, and combinationsthereof. Of these, hydroxy groups are typical. The functional endcontent in the polymer will depend, for example, on the amount ofincorporation of the flexibility-improving component desired. Thefunctional end content can be, for example, from about 0.5 to 35 wt %based on the polymer, for example from about 1 to 10 wt %, or from about2 to 5 wt %.

The polymer can further, optionally include one or more siloxane units,for example, phenyl or methyl-substituted siloxanes.

The described polymer materials can be prepared by known methods withreadily available starting materials. For example, a 50:50 methyl-phenylsilicon containing copolymer can be synthesized by condensation reactionof 50 wt % methyl-triethoxy-silane and 50 wt % phenyl-triethoxy-silane.

A first component for altering the solubility of the composition in thedried state can be an active component that is present in thecomposition to allow the composition to be alterable in its solubilityin a developer. In the case of a negative working material, it isthought that the active component catalyzes coupling of exposed portionsof the polymer composition, rendering the coupled portions insoluble inan aqueous developer. The active component typically generates an acidor base upon activation. A wide variety of active components may be usedin the present invention, including, but not limited to, photoacidgenerators, photobase generators, thermal acid generators and thermalbase generators. Of these, photoacid and thermal acid generators,components generating an acid upon activation, are typical.

The photoacid generators useful in the present invention can be anycompound or compounds which generate acid upon exposure to light.Suitable photoacid generators are known and include, but are not limitedto, halogenated triazines, onium salts, sulfonated esters, substitutedhydroxyimides, substituted hydroxylimines, azides, naphthoquinones suchas diazonaphthoquinones, diazo compounds, and combinations thereof.

Particularly useful halogenated triazines include, for example,halogenated alkyl triazines such as the trihalomethyl-s-triazines. Thes-triazine compounds are condensation reaction products of certainmethyl-trihalomethyl-s-triazines and certain aldehydes or aldehydederivatives. Such s-triazine compounds may be prepared according to theprocedures disclosed in U.S. Pat. No. 3,954,475 and Wakabayashi et al.,Bulletin of the Chemical Society of Japan, 42, 2924–30 (1969). Othertriazine type photoacid generators useful in the present invention aredisclosed, for example, in U.S. Pat. No. 5,366,846.

Onium salts with weakly nucleophilic anions are particularly suitablefor use as photoacid generators in the present invention. Examples ofsuch anions are the halogen complex anions of divalent to heptavalentmetals or non-metals, for example, antimony, tin, iron, bismuth,aluminum, gallium, indium, titanium, zirconium, scandium, chromium,hafnium, copper, boron, phosphorus and arsenic. Examples of suitableonium salts include, but are not limited to, diazonium salts such asdiaryl-diazonium salts and onium salts of group VA and B, IIA and B andI of the Periodic Table, for example, halonium salts such as iodoniumsalts, quaternary ammonium, phosphonium and arsonium salts, sulfoniumsalts such as aromatic sulfonium salts, sulfoxonium salts or seleniumsalts. Examples of suitable onium salts are disclosed, for example, inU.S. Pat. Nos. 4,442,197; 4,603,101; and 4,624,912. Sulfonium salts suchas triphenylsulfonium hexafluorophosphate and mixtures thereof arepreferred.

The sulfonated esters useful as photoacid generators in the presentinvention include, for example, sulfonyloxy ketones. Suitable sulfonatedesters include, but are not limited to, benzoin tosylate, t-butylphenylalpha-(p-toluenesulfonyloxy)-acetate, 2,6-dinitrobenzyl tosylate, andt-butyl alpha-(p-toluenesulfonyloxy)-acetate. Such sulfonated esters aredisclosed, for example, in the Journal of Photopolymer Science andTechnology, vol. 4, No. 3,337–340 (1991).

Substituted hydroxyimides which can be used include, for example,n-trifluoromethylsulfonyloxy-2,3-diphenylmaleimide and2-trifluoromethylbenzenesulfonyloxy-2,3-diphenylmaleimide. Suitablesubstituted hydroxylimines include, for example,2-(-nitrilo-2-methylbenzylidene)-(5-hydroxyiminobutylsulfonyl)-thiophene.Azides useful in the present invention include, for example,2,6-(4-azidobenzylidene)cyclohexanone. Naphthoquinones can include, forexample, 2,1-diazonaphthoquinone-4-sulfonate ester of2,3,4-trihydroxybenzophenone. Among the diazo compounds,1,7-bis(4-chlorosulonyl phenyl)-4-diazo-3,5-heptanedione can be used.

Photobase generators useful in the present invention can be any compoundor compounds which liberate base upon exposure to light. Suitablephotobase generators include, but are not limited to, benzyl carbamates,benzoin carbamates, O-carbamoylhydroxyamines, O-carbamoyloximes,aromatic sulfonamides, alpha-lactams, N-(2-allylethenyl)amides,arylazide compounds, N-arylformamides,4-(orthonitrophenyl)dihydropyridines, and combinations thereof.

Thermal acid generators useful in the present invention can be anycompound or compounds which generate an acid on heat activation. Theheat can be supplied by indirect methods such as convection heating orby direct heating methods such as laser heating techniques.

Suitable thermal acid generators are known and include, but are notlimited to, halogenated triazines, ammonium salts of acids, onium salts,sulfonated esters, substituted hydroxyimides, substitutedhydroxylimines, azides, naphthoquinones such as diazonaphthoquinones,diazo compounds, and combinations thereof.

The amount of the component for altering the solubility useful in thepresent invention, in the case of a negative working material, is anyamount sufficient to catalyze coupling of the silicon-containing polymerupon exposure to actinic radiation or heat to render the coupled portioninsoluble in an aqueous developer. The active component is present inthe composition in an amount of from 0.1 to 25 wt %, for example from0.1 to 12 wt %.

One or more components for improving the flexibility of the compositionin a dried state before and after activation are present in thecomposition. These flexibility-improving materials contain a pluralityof functional groups chosen from hydroxy, amino, thiol, sulphonateester, carboxylate ester, silyl ester, anhydride, aziridine,methylolmethyl, silyl ether, and combinations thereof. In theflexibility-improving materials, the functional groups are attached tobackbone materials. Exemplary backbone materials include substituted andunsubstituted alkyl and aryl hydrocarbons, ethers, acrylates, novolacs,polyimides, polyurethanes, polyesters, polysulfones, polyketones,fullerenes, POSS silicons, nanoparticles, and combinations thereof. Thefunctional groups can be present as end groups on the backbone and/or atone or more locations along the backbone.

Although not to be held to theory, it is believed that thefunctionalized component intermingles with the polymer to interruptcrystallinity relating brittleness of the coating. During the activationstep, the functional groups on the ends or throughout the backbone reactwith the functional end groups of the polymer causing a flexibilizinglink to the activated portion of the composition.

Examples of flexibilizing components are polyols of formula R²(OH)_(x)wherein R² is an organic group chosen from substituted or unsubstituted(C₂–C₂₅) alkyl, (C₇–C₂₅) aryl, (C₈–C₂₅) aralkyl, (C₆–C₂₅) cycloalkyl,and combinations thereof, wherein x is 2 or more and does not exceed thenumber of carbon atoms. When x is 2, examples of the flexibilizingcomponent include glycols, which are 1,2 diols, such asHOCH₂—CHOH—(CH₂)_(y)—CH₃ wherein y can be, for example, from 0 to 22,such as propylene glycol and butylene glycol. Other examples includeα,ω-diols such as HO—(CH₂)_(z)—OH wherein z is, for example, from 2 to25 such as ethylene glycol, 1,3-propanediol and 1,4-butanediol. When xis 3 examples include glycerin and trimethylolpropane.

R² can also be a polyether of formula —O—(CR³ ₂)_(w)— wherein w is, forexample, from 1 to 13 and R³ is the same or different and can be, forexample, H, or a substituted or unsubstituted organic group of formulaC₁–C₁₂ alkyl, aryl, aralkyl or cycloalkyl. Examples of flexibilizingcomponents include polyether diols of polyethylene oxide, polypropyleneoxide, polybutylene oxide, and polytetrahydrofurane.

The flexibility-improving component can have a weight average molecularweight, for example, of from 62 to 5000, for example from 62 to 2000.This component is present in an effective amount to improve theflexibility of the composition in a dried state before and afteractivation. The specific amount will depend, for example on the backboneand type of and number of functional groups of the flexibility-improvingcomponent. This component can, for example, be present in thecomposition in an amount of from 0.5 to 35 wt %, for example from 2 to20 wt %.

Other additives may optionally be present in the compositions of theinvention including, but are not limited to, surface leveling agents,wetting agents, antifoam agents, adhesion promoters, thixotropic agents,and the like. Such additives are well known in the art for coatingcompositions. The use of surface leveling agents, for examplesilicone-base oils such as SILWET L-7604 silicone-base oil availablefrom Dow Chemical Company, in the inventive compositions can be used. Itwill be appreciated that more than one additive may be combined in thecompositions of the present invention. For example, a wetting agent maybe combined with a thixotropic agent. Such optional additives arecommercially available from a variety of sources. The amounts of suchoptional additives to be used in the present compositions will depend onthe particular additive and desired effect, and are within the abilityof those skilled in the art. Such other additives are typically presentin the composition in an amount of less than 5 wt %, for example lessthan 2.5 wt %.

The compositions of the invention can optionally contain one or moreorganic cross-linking agents. Cross-linking agents include, for example,materials which link up components of the composition in athree-dimensional manner. Aromatic or aliphatic cross-linking agentsthat react with the silicon-containing polymer are suitable for use inthe present invention. Such organic cross-linking agents will cure toform a polymerized network with the silicon-containing polymer, andreduce solubility in a developer solution. Such organic cross-linkingagents may be monomers or polymers. It will be appreciated by thoseskilled in the art that combinations of cross-linking agents may be usedsuccessfully in the present invention.

Suitable organic cross-linking agents useful in the present inventioninclude, but are not limited to: amine containing compounds, epoxycontaining materials, compounds containing at least two vinyl ethergroups, allyl substituted aromatic compounds, and combinations thereof.Typical cross-linking agents include amine containing compounds andepoxy containing materials.

The amine containing compounds useful as cross-linking agents in thepresent invention include, but are not limited to: melamine monomers,melamine polymers, alkylolmethyl melamines, benzoguanamine resins,benzoguanamine-formaldehyde resins, urea-formaldehyde resins,glycoluril-formaldehyde resins, and combinations thereof.

It will be appreciated by those skilled in the art that suitable organiccross-linker concentrations will vary with factors such as cross-linkerreactivity and specific application of the composition. When used, thecross-linking agent(s) is typically present in the composition in anamount of from 0.1 to 50 wt %, for example, from 0.5 to 25 wt % or from1 to 20 wt %.

The present compositions can optionally contain one or more solvents.Such solvents aid in formulating the present compositions and in coatingthe present compositions on a substrate. A wide variety of solvents maybe used. Suitable solvents include, but are not limited to, glycolethers, such as ethylene glycol monomethyl ether, propylene glycolmonomethyl ether, dipropylene glycol monomethyl ether; esters such asmethyl cellosolve acetate, ethyl cellosolve acetate, propylene glycolmonomethyl ether acetate, dipropylene glycol monomethyl ether acetate,dibasic esters, carbonates such as propylene carbonate, γ-butyrolactone,esters such as ethyl lactate, n-amyl acetate and n-butyl acetate,alcohols such as n-propanol, iso-propanol, ketones such ascyclohexanone, methyl isobutyl ketone, diisobutyl ketone and2-heptanone, lactones such as γ-butyrolactone and γ-caprolactone, etherssuch as diphenyl ether and anisole, hydrocarbons such as mesitylene,toluene and xylene, and heterocyclic compounds such asN-methyl-2-pyrrolidone, N,N′-dimethylpropyleneurea, or mixtures thereof.

The compositions of the present invention can be prepared by combining,in admixture, the silicon-containing polymer, the catalytic component,and other optional components in any order.

The present compositions are particularly suitable for use in themanufacture of flexible optical waveguides. Optical waveguides can beused in forming opto-electrical devices including, but not limited to,splitters, couplers, spectral filters, polarizers, isolators,multiplexers such as wavelength division multiplexing structures,amplifiers, attenuators, switches, and the like or, on a larger scale,in electronic devices such as printed wiring boards, integratedcircuits, interconnects, and the like. The present photodefinablecompositions are also particularly useful in manufacturing displaydevices including lenses as well as optical elements such as mirrors,prisms and connectors. As used herein, the term electronic device isintended to encompass opto-electronic devices, for example, thosedescribed above, as well as the aforementioned larger scale devices thatinclude an opto-electronic device.

The waveguides of the present invention may be manufactured asindividual waveguides or as an array of waveguides. A method ofpreparing a waveguide using the inventive composition involves: (a)forming a layer over a substrate from a composition as described above,and (b) activating at least a portion of the layer, wherein the layer isa clad or a core layer. The compositions of the current invention aresuitable for use in forming waveguide clad and/or core structures. Forpurposes of example only, a method of forming a flexible opticalwaveguide having clad and core structures formed from the inventivecompositions will be described. A waveguide is formed by depositing coreand first and second cladding layers. The clad of the final structurehas a lower index of refraction as compared to the core. Particularlyuseful waveguides include a core having an index of refraction of from1.4 to 1.7 and a cladding having an index of refraction of from 1.3 to1.69.

With reference to FIG. 1, any substrate 2 suitable for supporting awaveguide may be used with the present compositions and constructs.Suitable substrates include, but are not limited to, substrates used inthe manufacture of electronic devices such as printed wiring boards andintegrated circuits. Particularly suitable substrates include laminatesurfaces and copper surfaces of copper clad boards, copper foils,printed wiring board inner layers and outer layers, wafers used in themanufacture of integrated circuits such as silicon, gallium arsenide,and indium phosphide wafers, glass substrates including but not limitedto liquid crystal display (“LCD”) glass substrates, and substrates thatinclude dielectric coatings, cladding layers, and the like.

A first cladding layer 4 can be formed on the substrate surface 2. Thefirst cladding layer 4 (as well as the other waveguide layers to bedescribed) may be formed from the compositions of the invention, by anytechnique including, but not limited to, screen printing, curtaincoating, roller coating, slot coating, spin coating, flood coating,electrostatic spray, spray coating, or dip coating. When thecompositions and constructs of the present invention are spray coated, aheated spray gun may optionally be used. The viscosity of thecomposition may be adjusted to meet the requirements for each method ofapplication by viscosity modifiers, thixotropic agents, fillers and thelike. The first cladding layer is deposited to a thickness in the driedstate of from about 1 to 100 μm, for example, from about 10 to 50 μm.

The first cladding layer 4 can be cured, for example, thermally orphotolytically depending on the type of active component in the firstcladding composition. The thermal curing temperature is from 90° C. to300° C., for example from 90° C. to 220° C. Such curing typically occursover a period of from five seconds to one hour. Such curing may beaffected by heating the substrate in an oven or on a hot plate.Alternatively the waveguide clad can be flood exposed, for example, with1 to 2 Joules/cm² of actinic radiation followed by the thermal cure from90° C. to 300° C., for example from 90° C. to 220° C.

A core layer 6 is formed on the first clad layer formed from thecomposition of the invention. The core layer is coated to a thickness offrom about 1 to 100 μm, for example, from about 8 to 60 μm. The coatedsubstrate is then soft cured, such as by baking, to remove solvent inthe coating. Such curing may take place at various temperatures,depending upon the particular solvent chosen. Suitable temperatures areany that are sufficient to substantially remove any solvent present. Thesoft curing may be at any temperature from room temperature (25° C.) to300° C. depending, for example, on the substrate and the thermal budget.Such curing can occur, for example, over a period of from 5 seconds to60 minutes in an oven or on a hot plate.

After curing, the layer of the present composition can then be imaged byexposure to actinic radiation. Such methods include, for example,contact imaging, projection imaging, and laser direct write imaging,including laser direct write imaging by multiphoton absorption.Multiphoton absorption can, if desired, be used to form 3-dimensionalstructures within the layer. The exposure pattern, as defined, forexample, by mask 8 in FIG. 1, defines the geometry of the corewaveguide, which is typically but not necessarily on the order ofcentimeters to meters in length, and microns to hundreds of microns inwidth. Following exposure, the composition can be post exposure cured,typically at a temperature of from 40° to 170° C. Curing time may varybut is generally from about 30 seconds to about 1 hour. While notintending to be bound by theory, it is believed that, in the case of anegative-working material, upon exposure to actinic radiation thesilicon-containing polymer couples, rendering the exposed areas lesssoluble in a developer solution than the unexposed areas.

The unexposed areas may be removed, such as by contact with a suitabledeveloper, leaving only the exposed areas remaining on the substrate,thus forming core structures 6 in FIG. 1. The composition can bedevelopable in an aqueous developer solution. Suitable aqueousdevelopers include, for example, alkali metal hydroxides such as sodiumhydroxide and potassium hydroxide in water, as well astetraalkylammonium hydroxide such as tetramethylammonium hydroxide, inwater. Such developers are typically used in concentrations from 0.1 to2N, for example, 0.15 to 1N, or 0.26 to 0.7N. The developer solutionsmay optionally include one or more known surfactants, such aspolyethylene glycol, alkyl sulfonates, and other surfactants well knownin the art. The surfactant is typically present in the developer in anamount of from 0.01 to 3 wt %. Antifoaming agents may also beadvantageously included in the developer.

The unexposed areas may alternatively be removed leaving only theexposed areas remaining on the substrate by contact with a non-aqueousdeveloper. Suitable non-aqueous developers include, for example,ketones, for example acetone, methyl ethyl ketone, methyl isobutylketone, cyclohexanone, 2-octanone, 2-heptanone and methyl isoamylketone; alcohols such as ethanol, isopropanol, n-propanol, n-butanol,isobutanol and amylol; esters such as ethyl acetate, ethyl propionateand ethyl lactate; glycol ethers such as ethylene glycol methyl ether,propylene glycol ethyl ether, propylene glycol methyl ether; glycolether esters such as ethylene glycol monomethyl ether acetate andpropylene glycol mono methyl ether acetate; aromatics such as toluene,xylene, chlorobenzene, dichlorobenzene and the like, and combinationsthereof.

Semi-aqueous developers can also be used which as combinations of theaqueous developer mentioned above and non-aqueous developers alsomentioned above.

Such development may be at a variety of temperatures such as from roomtemperature to about 65° C., for example from 21 to 49° C. Developmenttime with aggressive agitation can be within ten minutes, for example,within five minutes, within two minutes, within one minute, or within 30seconds. Development can take place, for example, in a staticdevelopment chamber or on a conveyorized platform upon which developeris sprayed. Spray pressures can range from 5 to 40 psi, for example,from 10 to 25 psi.

Following development, the present waveguides may undergo a final curestep. The curing can, for example, include a flood exposure, forexample, with 1 to 2 Joules/cm² of actinic radiation. Additionally, oralternatively, the waveguides may be heated at a temperature of fromabout 130° to 300° C. in air or an inert atmosphere such as nitrogen orargon. Next, a second cladding layer 10 can be formed as described aboveover the first cladding layer 4 and core structure 6′. The secondcladding layer may be the same or different from the first claddinglayer. The second cladding layer can be thermally activated and/or photoactivated to provide a waveguide structure as described above withrespect to the first clad layer. The second cladding layer is typicallydeposited to a thickness of from about 1 to 100 μm, for example, fromabout 10 to 50 μm.

Optical waveguides of the present invention possess excellenttransparencies at a variety of wavelengths. Thus, the present opticalwaveguides may be used at, for example, 600 to 1700 nm. It will beappreciated that the present optical waveguides may be advantageouslyused at other wavelengths. Thus, the present optical waveguides areparticularly suited for use in data communications andtelecommunications applications.

FIG. 2 illustrates an exemplary electronic device in accordance with afurther aspect of the invention. The electronic device is an opticalsplitter that includes a waveguide core 6′ formed on a waveguide clad 4.An input of signal wavelength, λ, is split at the Y-junction 12 into twolight signals, λ′, of equal wavelength but at a reduced power amplitude.

The following examples are intended to illustrate further variousaspects of the present invention, but are not intended to limit thescope of the invention in any aspect. The wt % as used in the examplesare based on full compositions including solvent.

EXAMPLE 1

40.74 wt % propylene glycol monomethyl ether acetate, 53.76 wt %phenyl-methyl-dimethylsilsesquioxane (49:49:2 wt % based on polymer),5.38 wt % polytetrahydrofurane, 0.11 wt % diphenylnaphthylsulfoniumperfluorobutanesulfonate, and 0.01 wt % Dow SILWET L-7604 silicone-baseoil were combined in admixture. The composition was coated onto apumice-scrubbed copper clad laminate using a number 80 drawdown bar. Thecoated laminate was dried in an oven at 90° C. for 30 minutes. Artworkdefining the required waveguide was placed directly on the composition.The artwork included patterns for forming waveguides of variousdimensions and shapes, such as linear, branched, and curved shapedwaveguides between 2 and 14 cm in length and 15 to 50 μm in width. Thecoated laminate was exposed at 500 mJ and placed in an oven at 90° C.for 15 minutes. The exposed laminate was then dipped in a 0.7N sodiumhydroxide developer solution held at 37.8° C. (100° F.) for 30 seconds.The laminate was then rinsed in de-ionized water and dried. The laminatewas heated to 200° C. for 60 minutes in an oven. The waveguide was bentover a 1/16 inch diameter mandrel. The base laminate cracked but thecoating did not crack based on visual inspection.

EXAMPLE 2

50 wt % propylene glycol monomethyl ether acetate, 42 wt % phenyl-methylsilsesquioxane (60:40 wt % based on polymer), 5 wt % ofdihydroxy-terminated polyethylene oxide, 2.99 wt % triphenylsulfoniumhexafluorophosphate, and 0.01 wt % Dow SILWET L-7604 silicone-base oilare combined in admixture. The composition is roller-coated onto 24inch×36 inch (61 cm×91.4 cm) epoxy laminate, such as is commonly used inprinted wiring board manufacture, to a thickness of 60 μm. Thecomposition is then dried in air in a convection oven for 45 minutes at90° C. Artwork as described in Example 1, but with line widths of 40 to200 μm, is placed directly on the composition. 1000 mJ/cm² of actinicradiation is applied to the construction, followed by apost-exposure-bake in air at 90° C. for 30 minutes. The exposedstructure is then placed into a spray developer containing 0.7N sodiumhydroxide developer solution held at 37.8° C. (100° F.) for a total of120 seconds. The laminate is rinsed in de-ionized water and dried. Theresultant waveguides are flood-exposed with 2000 mJ/cm² of actinicradiation, followed by hard cure at 180° C. for 120 minutes in air in aconvection oven. Flexible optical waveguides are expected to be formed.

EXAMPLE 3

45 wt % propylene glycol monomethyl ether acetate, 25 wt % oftrifluoromethyl-phenyl-silsesquioxane (10:90 wt % based on polymer), 15wt % polytetrahydrofurane, 4.95 wt % benzoin tosylate, and 0.05 wt % DowSILWET L-7604 silicone-base oil are combined in admixture. Thecomposition is spin-coated at 2500 rpm onto a six-inch silicondioxide-coated silicon wafer and soft-baked in air on a hot plate fortwo minutes at 90° C., to a thickness of 8 μm. Artwork as described inExample 1 is placed directly on the composition. 2000 mJ/cm² of actinicradiation is applied to the construction followed by apost-exposure-bake in air at 90° C. for two minutes. The exposed waferis then dipped in a propylene glycol monomethyl ether acetate developersolution held at 37.8° C. (100° F.) for 30 seconds. The wafer is thenrinsed in de-ionized water and dried. The wafer is heated to 200° C. inair for 10 minutes on a hot plate. Flexible optical waveguides areexpected to be formed.

EXAMPLE 4

37 wt % propylene glycol monomethyl ether acetate, 47.99 wt %methyl-phenyl silsesquioxane (50:50 wt % based on polymer), 10 wt %polyvinyl phenol, 5 wt % triphenylsulfonium trifluoromethylsulphonate,and 0.01 wt % Dow SILWET L-7604 silicone-base oil are combined inadmixture. The composition is roller-coated onto 24 inch×36 inch (61cm×91.4 cm) epoxy laminate, such as is commonly used in printed wiringboard manufacture, to a thickness of 60 μm. The composition is thendried in air in a convection oven for 45 minutes at 90° C. Artwork asdescribed in Example 1, but with line widths of 40 to 200 μm, is placeddirectly on the composition. 1000 mJ/cm² of actinic radiation is appliedto the construction, followed by a post-exposure-bake in air at 90° C.for 30 minutes. The exposed structure is then placed into a spraydeveloper containing 0.7N sodium hydroxide developer solution held at37.8° C. (100° F.) for a total of 120 seconds. The laminate is rinsed inde-ionized water and dried. The resultant waveguides are flood-exposedwith 2000 mJ/cm² of actinic radiation, followed by hard cure at 180° C.for 120 minutes in air in a convection oven. Flexible optical waveguidesare expected to be formed.

EXAMPLE 5

30 wt % propylene glycol monomethyl ether acetate, 54.99 wt %methyl-phenyl silsesquioxane (40:60 wt % based on polymer), 10 wt % poly(1,4-butylene adipate), diol end-capped, 5 wt % triphenylsulfoniumtrifluoromethylsulphonate, and 0.01 wt % Dow SILWET L-7604 silicone-baseoil are combined in admixture. The composition is roller-coated onto 24inch×36 inch (61 cm×91.4 cm) epoxy laminate, such as is commonly used inprinted wiring board manufacture, to a thickness of 50 μm. Thecomposition is then dried in air in a convection oven for 30 minutes at90° C. Artwork as described in Example 1, but with line widths of 40 to200 μm, is placed directly on the composition. 800 mJ/cm² of actinicradiation is applied to the construction, followed by apost-exposure-bake in air at 90° C. for 30 minutes. The exposedstructure is then placed into a spray developer containing 0.7N sodiumhydroxide developer solution held at 37.8° C. (100° F.) for a total of120 seconds. The laminate is rinsed in de-ionized water and dried. Theresultant waveguides are hard cured at 180° C. for 120 minutes in air ina convection oven. Flexible optical waveguides are expected to beformed.

EXAMPLE 6

40 wt % propylene glycol monomethyl ether acetate, 49.99 wt %methyl-phenyl silsesquioxane (40:60 wt % based on polymer), 5 wt %polycaprolactone triol, 5 wt % triphenylsulfoniumtrifluoromethylsulphonate, and 0.01 wt % Dow SILWET L-7604 silicone-baseoil are combined in admixture. The composition is roller-coated onto 24inch×36 inch (61 cm×91.4 cm) epoxy laminate, such as is commonly used inprinted wiring board manufacture, to a thickness of 50 μm. Thecomposition is then dried in air in a convection oven for 30 minutes at90° C. Artwork as described in Example 1, but with line widths of 40 to200 μm, is placed directly on the composition. 800 mJ/cm² of actinicradiation is applied to the construction, followed by apost-exposure-bake in air at 90° C. for 30 minutes. The exposedstructure is then placed into a spray developer containing 0.7N sodiumhydroxide developer solution held at 37.8° C. (100° F.) for a total of120 seconds. The laminate is rinsed in de-ionized water and dried. Theresultant waveguides are hard cured at 180° C. for 120 minutes in air ina convection oven. Flexible optical waveguides are expected to beformed.

EXAMPLE 7

Clad Layer

A clad layer composition was formed by combining in admixture 40.61 wt %propylene glycol monomethyl ether acetate, 53.47 wt %phenyl-methyl-dimethylsilsesquioxane (49:49:2 wt % based on polymer),5.35 wt % polytetrahydrofurane, 0.56 wt % amine blockeddodecylphenylsulphate and 0.01 wt % Dow SILWET L-7604 silicone-base oil.The composition was coated onto a mechanically scrubbed copper laminateusing a number 80 drawdown bar. The laminate was dried in an oven for 30minutes at 90° C. followed by a hard baked at 180° C. for 1 hour in theoven.

Core

The clad layer was coated with a core composition formed by admixing35.75 wt % propylene glycol monomethyl ether acetate, 56.44 wt %phenyl-methyl-dimethylsilsesquioxane (49:49:2 wt % based on polymer),6.24 wt % polytetrahydrofurane, 1.56 wt % diphenylnaphthylsulfoniumperfluorobutanesulphate and 0.01 wt % Dow SILWET L-7604 silicone-baseoil. The coated laminate was dried in an oven at 90° C. for 30 minutes.Artwork defining the required waveguide was placed directly on thecomposition. The artwork included patterns for forming waveguides ofvarious dimensions and shapes, such as linear, branched, and curvedshaped waveguides between 2 and 14 cm in length and 15 to 50 μm inwidth. The coated laminate was exposed at 500 mJ and placed in an ovenat 90° C. for 15 minutes. The coated laminate was then dipped in a 0.7Nsodium hydroxide developer solution held at 37.8° C. for 30 seconds. Thecoated laminate was then rinsed in de-ionized water and dried. Thecoated laminate was heated to 200° C. for 60 minutes in an oven. Thewaveguide was bent over a 1/16 inch diameter mandrel. The base laminatecracked but the clad and core layers did not crack based on visualinspection.

EXAMPLE 8

Clad (1) Layer

A first cladding layer composition is formed by combining in admixture39 wt % propylene glycol monomethyl ether acetate, 48.5 wt %phenyl-methyl-dimethylsilsesquioxane (35:65 wt % based on polymer), 7.5%dihydroxy-terminated polyethylene oxide, 4.99 wt % of amine blockeddodecylphenylsulphate, and 0.01 wt % Dow SILWET L-7604 silicone-baseoil. The composition is roller-coated onto 24 inch×36 inch (61 cm×91.4cm) epoxy laminate, such as is commonly used in printed wiring boardmanufacture, to a thickness of 50 μm. The composition is then dried inair in a convection oven for 45 minutes at 90° C. The first-clad-coatedsubstrate is heated at 180° C. for 1.5 hours.

Core

The first cladding layer is coated with the core composition of Example2 and is patterned and cured as described in Example 2

Clad (2) Layer

A second cladding layer composition is formed over the patterned coreand first cladding layer using the same composition and procedures usedin forming the first cladding layer, except the thickness of the secondcladding layer after the soft-bake is 60 μm. Flexible optical waveguidesare expected to be formed.

EXAMPLE 9

Clad (1) Layer

A first cladding layer composition is formed by combining in admixtureof 50 wt % propylene glycol monomethyl ether acetate, 40.99 wt %phenyl-methyl silsesquioxane (40:60 wt % based on polymer), 4 wt %polytetrahydrofurane, 5 wt % triphenylsulfonium trifluoromethylsulphateand 0.01 wt % Dow SILWET L-7604 silicone-base oil. The composition isspin-coated at 2000 rpm onto a six-inch silicon dioxide-coated siliconwafer and soft-baked in air on a hot plate for two minutes at 90° C., toa thickness of 8 μm. The composition is exposed to 800 mJ, heated at 90°C. for 2 minutes on a hot plate. The composition is then hard-baked inair on a hot plate for ten minutes at 200° C.

Core

The first cladding layer is coated with the core composition of Example3 and patterned and cure as described in Example 3.

Clad (2) Layer

A second cladding layer composition is formed over the patterned coreand first cladding layer using the same composition and procedures usedin forming the first cladding layer, except the thickness of the secondcladding layer after the soft-bake is 10 μm. Flexible optical waveguidesare expected to be formed.

EXAMPLE 10

Clad (1) Layer

A first cladding layer composition is formed by combining in admixture39 wt % propylene glycol monomethyl ether acetate, 56 wt % phenyl-methylsilsesquioxane (50:50) wt % based on polymer), 10% dihydroxy-terminatedpolypropylene glycol, 4.99 wt % of amine blocked dodecylphenylsulphate,and 0.01 wt % Dow SILWET L-7604 silicone-base oil. The composition isroller-coated onto 24 inch×36 inch (61 cm×91.4 cm) epoxy laminate, suchas is commonly used in printed wiring board manufacture, to a thicknessof 50 μm. The composition is then dried in air in a convection oven for45 minutes at 90° C. The first-clad-coated substrate is heated at 180°C. for 1 hour.

Core

The first cladding layer is coated with the core composition of Example4 and is patterned and cured as described in Example 4.

Clad (2) Layer

A second cladding layer composition is formed over the patterned coreand first cladding layer using the same composition and procedures usedin forming the first cladding layer, except the thickness of the secondcladding layer after the soft-bake is 60 μm. Flexible optical waveguidesare expected to be formed.

EXAMPLE 11

Clad (1) Layer

A first cladding layer composition is formed by combining in admixture39 wt % propylene glycol monomethyl ether acetate, 56 wt % phenyl-methylsilsesquioxane (50:50) wt % based on polymer), 10% dihydroxy-terminatedpolypropylene glycol, 4.99 wt % of amine blocked dodecylphenylsulphate,and 0.01 wt % Dow SILWET L-7604 silicone-base oil. The composition isroller-coated onto 24 inch×36 inch (61 cm×91.4 cm) epoxy laminate, suchas is commonly used in printed wiring board manufacture, to a thicknessof 50 μm. The composition is then dried in air in a convection oven for45 minutes at 90° C. The first-clad-coated substrate is heated at 180°C. for 1 hour.

Core

The first cladding layer is coated with the core composition of Example5 and is patterned and cured as described in Example 5.

Clad (2) Layer

A second cladding layer composition is formed over the patterned coreand first cladding layer using the same composition and procedures usedin forming the first cladding layer, except the thickness of the secondcladding layer after the soft-bake is 60 μm. Flexible optical waveguidesare expected to be formed.

EXAMPLE 12

Clad (1) Layer

A first cladding layer composition is formed by combining in admixture39 wt % propylene glycol monomethyl ether acetate, 56 wt % phenyl-methylsilsesquioxane (50:50) wt % based on polymer), 10% dihydroxy-terminatedpolypropylene glycol, 4.99 wt % of amine blocked dodecylphenylsulphate,and 0.01 wt % Dow SILWET L-7604 silicone-base oil. The composition isroller-coated onto 24 inch×36 inch (61 cm×91.4 cm) epoxy laminate, suchas is commonly used in printed wiring board manufacture, to a thicknessof 50 μm. The composition is then dried in air in a convection oven for45 minutes at 90° C. The first-clad-coated substrate is heated at 180°C. for 1 hour.

Core

The first cladding layer is coated with the core composition of Example6 and is patterned and cured as described in Example 6.

Clad (2) Layer

A second cladding layer composition is formed over the patterned coreand first cladding layer using the same composition and procedures usedin forming the first cladding layer, except the thickness of the secondcladding layer after the soft-bake is 60 μm. Flexible optical waveguidesare expected to be formed.

While the invention has been described in detail with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made, and equivalentsemployed, without departing from the scope of the claims.

1. A composition comprising: a polymer, comprising units of the formula(RSiO_(1.5)) wherein R is a substituted or unsubstituted organic group,and a plurality of functional end groups; a first component for alteringthe solubility of the composition in a dried state upon activation; anda second component containing a plurality of functional groups chosenfrom hydroxy, amino, thiol, sulphonate ester, carboxylate ester, silylester, anhydride, aziridine, methylolmethyl, silyl ether, andcombinations thereof, wherein the second component is present in aneffective amount to improve flexibility of the composition in a driedstate before and after activation.
 2. The composition according to claim1, wherein the polymer further comprises units of the formula(R¹SiO_(1.5)), wherein R¹ is a substituted or unsubstituted organicgroup, and is different from R.
 3. The composition according to claim 1wherein the second component comprises a material chosen fromsubstituted and unsubstituted alkyl and aryl hydrocarbons, ethers,acrylates, novolacs, nanoparticles, polyimides, polyurethanes,polyesters, polysulfones, polyketones, fullerenes, POSS silicons, andcombinations thereof.
 4. The composition according to claim 1, whereinthe second component is a polyol.
 5. The composition according to claim1, wherein the second component is a polyether-diol.
 6. The compositionaccording to claim 1, wherein the first component generates an acid uponactivation.
 7. The composition according to claim 1, wherein thecomposition in the dried state is aqueous developable.
 8. A flexibleoptical waveguide, comprising a core and a clad, wherein the core and/orthe clad are formed from a composition comprising: a polymer, comprisingunits of the formula (RSiO_(1.5)) wherein R is a substituted orunsubstituted organic group, and a plurality of functional end groups; afirst component for altering the solubility of the composition in adried state upon activation; a second component containing a pluralityof functional groups chosen from hydroxy, amino, thiol, sulphonateester, carboxylate ester, silyl ester, anhydride, aziridine,methylolmethyl, silyl ether, and combinations thereof, wherein thesecond component is present in an effective amount to improveflexibility of the composition in a dried state before and afteractivation.
 9. The flexible optical waveguide according to claim 8,wherein the polymer further comprises units of the formula(R¹SiO_(1.5)), wherein R¹ is a substituted or unsubstituted organicgroup, and is different from R.
 10. The flexible optical waveguideaccording to claim 8, wherein the second component comprises a materialchosen from substituted and unsubstituted alkyl and aryl hydrocarbons,ethers, acrylates, novolacs, nanoparticles, polyimides, polyurethanes,polyesters, polysulfones, polyketones, fullerenes, POSS silicons, andcombinations thereof.
 11. The flexible optical waveguide according toclaim 8, wherein the second component is a polyol.
 12. The flexibleoptical waveguide according to claim 8, wherein the second component isa polyether-diol.
 13. An electronic device, comprising a flexibleoptical waveguide according to claim
 8. 14. A method of forming aflexible optical waveguide comprising a core and a clad, the methodcomprising: (a) forming a layer over a substrate from a compositioncomprising a polymer, comprising units of the formula (RSiO_(1.5))wherein R is a substituted or unsubstituted organic group, and aplurality of functional end groups; and a first component for alteringthe solubility of the composition in a dried state upon activation; asecond component containing a plurality of functional groups chosen fromhydroxy, amino, thiol, sulphonate ester, carboxylate ester, silyl ester,anhydride, aziridine, methylolmethyl, silyl ether, and combinationsthereof, wherein the second component is present in an effective amountto improve flexibility of the composition in a dried state before andafter activation, and (b) activating at least a portion of the layer,wherein the layer is a core or a clad layer.
 15. The method according toclaim 14 wherein the second component comprises a material chosen fromsubstituted and unsubstituted alkyl and aryl hydrocarbons, ethers,acrylates, novolacs, nanoparticles, polyimides, polyurethanes,polyesters, polysulfones, polyketones, fullerenes, POSS silicons, andcombinations thereof.
 16. The method according to claim 14, wherein thesecond component is a polyol.
 17. The method according to claim 14,wherein the layer is a core layer, and wherein (b) comprises activatinga portion of the core layer, and further comprising: (c) developing thecore layer to form a core structure.
 18. The method according to claim14, wherein the layer is a clad layer, and wherein (b) comprisesactivating the entire clad layer.
 19. The method according to claim 14,wherein the layer is a first clad layer, and further comprising: (c)forming a core layer over the clad layer from a second composition asdefined in (a) that is the same or different from the composition of(a); (d) activating a portion of the core layer; (e) developing the corelayer to form a core structure; and (f) forming a second clad layer overthe core structure from a third composition as defined in (a) that isthe same or different from the compositions of (a) and/or (c).
 20. Themethod according to claim 19, wherein the composition in the dried stateis aqueous developable.